.modal-window {
    position: fixed;
    background-color: rgba(0, 0, 0, 0.25);
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 999;
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s;
  }

 /* 弹窗 */  
  .modal-window:target {
    visibility: visible;
    opacity: 1;
    pointer-events: auto;
  }
  .modal-window > div {
    background-color: rgb(0, 0, 0);
    width: 600px;
    position: absolute;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
            transform: translate(-50%, -50%);
    padding: 2em;
    background: #ffffff;
  }
  .modal-window header {
    font-weight: bold;
  }
  .modal-window h1 {
    font-size: 150%;
    margin: 0 0 15px;
  }
/* 确定关闭弹窗 */
  .modal-close {
    color: rgb(0, 0, 0);
    line-height: 50px;
    font-size: 80%;
    position: absolute;
    right: 0;
    text-align: center;
    top: 0;
    width: 70px;
    text-decoration: none;
  }
  .modal-close:hover {
    color: black;
    font-weight: 700;
  }
  
  /* Demo Styles */
  html,
  body {
    height: 100%;
  }
  
  .modal-window div:not(:last-of-type) {
    margin-bottom: 15px;
  }
  